Zobrazeno 1 - 10
of 169
pro vyhledávání: '"Bethell, Thomas"'
Autor:
Ardila, David R., Herczeg, Gregory J., Gregory, Scott G., Ingleby, Laura, France, Kevin, Brown, Alexander, Edwards, Suzan, Johns-Krull, Christopher, Linsky, Jeffrey L., Yang, Hao, Valenti, Jeff A., Abgrall, Hervé, Alexander, Richard D., Bergin, Edwin, Bethell, Thomas, Brown, Joanna M., Calvet, Nuria, Espaillat, Catherine, Hillenbrand, Lynne A., Hussain, Gaitee, Roueff, Evelyne, Schindhelm, Rebecca, Walter, Frederick M.
For Classical T Tauri Stars (CTTSs), the resonance lines of N V, Si IV, and C IV, as well as the He II 1640 A line, act as diagnostics of the accretion process. Here we assemble a large high-resolution dataset of these lines in CTTSs and Weak T Tauri
Externí odkaz:
http://arxiv.org/abs/1304.3746
Autor:
Cleeves, L. Ilsedore, Bergin, Edwin A., Bethell, Thomas J., Calvet, Nuria, Fogel, Jeffrey K. J., Sauter, Juergen, Wolf, Sebastian
We explore the chemical structure of a disk that contains a large central gap of R ~ 45 AU, as is commonly seen in transitional disk systems. In our chemical model of a disk with a cleared inner void, the midplane becomes revealed to the central star
Externí odkaz:
http://arxiv.org/abs/1111.0010
Autor:
Ingleby, Laura, Calvet, Nuria, Bergin, Edwin, Herczeg, Gregory, Brown, Alexander, Alexander, Richard, Edwards, Suzan, Espaillat, Catherine, France, Kevin, Gregory, Scott G., Hillenbrand, Lynne, Roueff, Evelyne, Valenti, Jeff, Walter, Frederick, Johns-Krull, Christopher, Brown, Joanna, Linsky, Jeffrey, McClure, Melissa, Ardila, David, Abgrall, Herve, Bethell, Thomas, Hussain, Gaitee, Yang, Hao
Young stars surrounded by disks with very low mass accretion rates are likely in the final stages of inner disk evolution and therefore particularly interesting to study. We present ultraviolet (UV) observations of the ~5-9 Myr old stars RECX-1 and R
Externí odkaz:
http://arxiv.org/abs/1110.6312
Autor:
Bethell, Thomas, Bergin, Edwin
We study the role resonant scattering plays in the transport of Lyman-alpha photons in accreting protoplanetary disk systems subject to varying degrees of dust settling. While the intrinsic stellar FUV spectrum of accreting T Tauri systems may alread
Externí odkaz:
http://arxiv.org/abs/1107.3514
Autor:
Bethell, Thomas, Bergin, Edwin
We provide simple polynomial fits to the X-ray photoelectric cross-sections (0.03 < E < 10keV) for mixtures of gas and dust found in protoplanetary disks. Using the solar elemental abundances of Asplund et al. (2009) we treat the gas and dust compone
Externí odkaz:
http://arxiv.org/abs/1107.3515
Autor:
France, Kevin, Schindhelm, Rebecca, Burgh, Eric B., Herczeg, Gregory J., Harper, Graham M., Brown, Alexander, Green, James C., Linsky, Jeffrey L., Yang, Hao, Abgrall, Hervé, Ardila, David R., Bergin, Edwin, Bethell, Thomas, Brown, Joanna M., Calvet, Nuria, Espaillat, Catherine, Gregory, Scott G., Hillenbrand, Lynne A., Hussain, Gaitee, Ingleby, Laura, Johns-Krull, Christopher M., Roueff, Evelyne, Valenti, Jeff A., Walter, Frederick M.
We exploit the high sensitivity and moderate spectral resolution of the $HST$-Cosmic Origins Spectrograph to detect far-ultraviolet spectral features of carbon monoxide (CO) present in the inner regions of protoplanetary disks for the first time. We
Externí odkaz:
http://arxiv.org/abs/1104.0670
We present results from a model of the chemical evolution of protoplanetary disks. In our models we directly calculate the changing propagation and penetration of a high energy radiation field with Lyman alpha radiation included. We also explore the
Externí odkaz:
http://arxiv.org/abs/1011.0446
Publikováno v:
Astrophys.J. 610 (2004) 801-812
We have calculated the radiation field, dust grain temperatures, and far infrared emissivity of numerical models of turbulent molecular clouds. When compared to a uniform cloud of the same mean optical depth, most of the volume inside the turbulent c
Externí odkaz:
http://arxiv.org/abs/astro-ph/0404056
Autor:
Gnedin, Nickolay Y., Baker, Emily J., Bethell, Thomas J., Drosback, Meredith M., Harford, A. Gayler, Hicks, Amalia K., Jensen, Adam G., Keeney, Brian A., Kelso, Christopher M., Neyrinck, Mark C., Pollack, Scott E., van Vliet, Timothy P.
Publikováno v:
Astrophys.J. 583 (2003) 525-528
We investigate the relationship between the dark matter and baryons in the linear regime. This relation is quantified by the so-called ``filtering scale''. We show that a simple gaussian ansatz which uses the filtering scale provides a good approxima
Externí odkaz:
http://arxiv.org/abs/astro-ph/0206421
Autor:
Bethell, Thomas, Bergin, Edwin
Publikováno v:
Science, 2009 Dec . 326(5960), 1675-1677.
Externí odkaz:
https://www.jstor.org/stable/27736696
